LED lights of blue light if there is a harm to the eyes, can also be used in the future?

The first method is by regulating the LED drive current to achieve LED lamp dimming, because of the brightness of the LED chip and LED drive current has a fixed ratio.

Described in the second move light is often referred to as analog dimming mode or linear dimming. The advantage of this kind of dimming is: when the drive current linear increase or decrease, the relatively lower LED chip, strong immunity to the drive current control circuit of the effect of overshoot. The downside is that in drive current changes will produce certain effect, color temperature of LED chip.

The third way is a pulse of light that move light modulator (PWM) mode. This method is through certain control the drive current square, variable pulse width, through the duration of the pulse width adjustment to change, also can change the output power at the same time, so as to achieve the goal of energy saving. Frequency control of motor speed is in commonly 200 hz to 10 KHZ, visual retention due to people's eyes, let a person feel the light flashing light moving process. The advantage of this approach is mobile has the advantage that can improve the heat dissipation of the LED light. Its disadvantage is that the drive current overshoot some effect to the life of the LED chip.

All three of these dimmers method is based on the classification of the LED drive current of the output of the control. Control circuit can also be divided into analog control and PWM control, the control circuit is completed by micro controller usually.

2. The dimming system and the future development

Perfect intelligent control should have manual control, intelligent control, electric, control and fault alarm function. It was dimmed can automatically light up when the sun goes down, the midnight lamp can be automatically by half; The morning after, light can be automatically extinguished; Under special circumstances, people can be manual control; Control and failure occurs, the control system can automatically alarm.

Intelligent dimming system includes server, the central controller, single chip controller and four signal detection circuit.

Server: host and computer software, the main implementation of monitoring and alarm function. The web server is located in the street lamp management control center and the central controller can connect through the power line carrier, network or wireless way achived.

Central controller: responsible for receiving signals from the server and sent to the controller, control and signal detection, and send the result to the server decoding unit.

Signal detection circuit, testing environment brightness, drive power supply voltage, electric current. And the detected signal is sent to the unit controller or central controller.

Unit controller: each LED lamp is equipped with a unit controller, by receiving the instruction, the central controller, to control or turned on and off the LED light, at the same time will be LED by the driving voltage, current signal detection circuit of the central controller. When there is failure of LED lamps and lanterns to signal to the central controller.

At present in the field of road lighting, LED application is spreading fast, long service life and reliability is still considered one of the first things to do, but with the development of technology, when life and reliability problem is resolved, to a certain extent, LED lighting applications will inevitably to the pace of the intelligent dimming system.